Saltat senex, as it is in the proverb; he does triumph in his felicity, admires the party!
"Epicoene" by Ben Jonson
It was posturing rather than saltation.
"Samoa, A Hundred Years Ago And Long Before" by George Turner
In the heat of noon, in the cool of the evening, day after day there was no rest for them, their saltation was without end.
"Folk-lore and Legends: German" by Anonymous
Phoebe minor, however, executed gleeful saltations in honour of his arrival.
"Love's Usuries" by Louis Creswicke
Mr. Durnford found this Saltator "pretty common" near Baradero, on low scrubby ground near water, and afterwards obtained it near Salta.
"Argentine Ornithology, Volume I (of 2)" by P. L. Sclater
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They showed that the typical time to reach the equilibrium state in saltation on a ﬂat surface is approximately two seconds, which was later conﬁrmed by wind tunnel measurements .
A Continuum Saltation Model for Sand Dunes
In section V we disregard the spatial dependence of the sand ﬂux and concentrate on the time evolution of the saltation layer.
A Continuum Saltation Model for Sand Dunes
The saltation transport can conceptually be divided into four sub–processes.
A Continuum Saltation Model for Sand Dunes
The typical tra jectory of a saltating grain intersects with each height level z two times, once when ascending and once when descending.
A Continuum Saltation Model for Sand Dunes
Sketch of the horizontal sand ﬂux q caused by saltating grains passing the vertical rectangle.
A Continuum Saltation Model for Sand Dunes
The average saltation length l and the average saltation time T are related by l = u T .
A Continuum Saltation Model for Sand Dunes
The typical values for the time and length of a mean saltation tra jectory depend on the shear velocity u∗ , T (u∗) ≈ 1.7 u∗/g and l(u∗ ) ≈ 18 u2 ∗/g .
A Continuum Saltation Model for Sand Dunes
It is important to realize that the air born shear stress within the saltation layer, and therewith n, is lowered if the number of grains in the saltation layer increases and vice versa.
A Continuum Saltation Model for Sand Dunes
For τa0 > τt , the number of grains in the saltation layer increases in a chain reaction (n > 1) whereas for τa0 < τt (n < 1) saltation cannot be maintained.
A Continuum Saltation Model for Sand Dunes
These directly entrained grains have been neglected up to now, because they are only important to initiate saltation [10, 11].
A Continuum Saltation Model for Sand Dunes
In section III we introduced the drag and friction forces, fdrag and fbed , acting on the saltation layer.
A Continuum Saltation Model for Sand Dunes
But saltating grains in the air change the air shear stress and the wind speed.
A Continuum Saltation Model for Sand Dunes
Furthermore, we have introduced two model parameters α and z1 determining the equilibrium state of the saltation layer, and the parameter γ that controls the relaxation to equilibrium.
A Continuum Saltation Model for Sand Dunes
In the following sections we will ﬁrst discuss the fully saturated situation and later some dynamical properties of the saltation layer.
A Continuum Saltation Model for Sand Dunes
The full dynamics of the saltation layer must be evaluated numerically, whereas the saturated ﬂux — the stationary solution (∂ /∂ t = 0) for a constant external shear stress (τ (x, t) = τ ) and a homogeneous bed (∂ /∂ x = 0) — can be calculated analytically from Eq.(29) and (33).
A Continuum Saltation Model for Sand Dunes
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